When my daughter was young, our neighbor boy had a large pointy lump on his clavicle from a break that wasn't set. They didn't know it was broken until much later (years) but, He was an extremely small boy...very, very skinny, and it was so obvious to people because he was so thin. When he and my dd would play rough, I worried about her hurting him because he looked so frail.

They did not think it was something that happened at birth. They think it happened somewhere around age three or four. (I guess he was that kind of kid who was always breaking something)

Anyway...he's 21 years old now... has bulked up his body a little and I saw him at the gym last night in a tank top, and you can't see the bump at all. He's still lanky, but not as frail...so, it is either under muscle and fat, or he outgrew it, or it just went away. I bet he hasn't even thought about it in years.